3,190 research outputs found
Resonant Anomaly Detection with Multiple Reference Datasets
An important class of techniques for resonant anomaly detection in high
energy physics builds models that can distinguish between reference and target
datasets, where only the latter has appreciable signal. Such techniques,
including Classification Without Labels (CWoLa) and Simulation Assisted
Likelihood-free Anomaly Detection (SALAD) rely on a single reference dataset.
They cannot take advantage of commonly-available multiple datasets and thus
cannot fully exploit available information. In this work, we propose
generalizations of CWoLa and SALAD for settings where multiple reference
datasets are available, building on weak supervision techniques. We demonstrate
improved performance in a number of settings with realistic and synthetic data.
As an added benefit, our generalizations enable us to provide finite-sample
guarantees, improving on existing asymptotic analyses
Overcoming exponential volume scaling in quantum simulations of lattice gauge theories
Real-time evolution of quantum field theories using classical computers
requires resources that scale exponentially with the number of lattice sites.
Because of a fundamentally different computational strategy, quantum computers
can in principle be used to perform detailed studies of these dynamics from
first principles. Before performing such calculations, it is important to
ensure that the quantum algorithms used do not have a cost that scales
exponentially with the volume. In these proceedings, we present an interesting
test case: a formulation of a compact U(1) gauge theory in 2+1 dimensions free
of gauge redundancies. A naive implementation onto a quantum circuit has a gate
count that scales exponentially with the volume. We discuss how to break this
exponential scaling by performing an operator redefinition that reduces the
non-locality of the Hamiltonian. While we study only one theory as a test case,
it is possible that the exponential gate scaling will persist for formulations
of other gauge theories, including non-Abelian theories in higher dimensions.Comment: 11 pages, 2 figures, Proceedings of the 39th Annual International
Symposium on Lattice Field Theory (Lattice 2022), August 8-13 2022, Bonn,
German
A convergent algorithm for the hybrid problem of reconstructing conductivity from minimal interior data
We consider the hybrid problem of reconstructing the isotropic electric
conductivity of a body from interior Current Density Imaging data
obtainable using MRI measurements. We only require knowledge of the magnitude
of one current generated by a given voltage on the boundary
. As previously shown, the corresponding voltage potential u in
is a minimizer of the weighted least gradient problem
with . In this paper we present an
alternating split Bregman algorithm for treating such least gradient problems,
for non-negative and . We
give a detailed convergence proof by focusing to a large extent on the dual
problem. This leads naturally to the alternating split Bregman algorithm. The
dual problem also turns out to yield a novel method to recover the full vector
field from knowledge of its magnitude, and of the voltage on the
boundary. We then present several numerical experiments that illustrate the
convergence behavior of the proposed algorithm
Adaptive introgressive hybridization with the Algerian mouse (Mus spretus) promoted the evolution of anticoagulant rodenticide resistance in European house mice (M. musculus domesticus)
Song, Y., Endepols, S., Klemann, N., Richter, D., Matuschka, F.-R., Shih, C.-H., Nachman, M.W., Kohn, M.H
Calomplification — the power of generative calorimeter models
Motivated by the high computational costs of classical simulations, machine-learned generative models can be extremely useful in particle physics and elsewhere. They become especially attractive when surrogate models can efficiently learn the underlying distribution, such that a generated sample outperforms a training sample of limited size. This kind of GANplification has been observed for simple Gaussian models. We show the same effect for a physics simulation, specifically photon showers in an electromagnetic calorimeter
Evidence for Pervasive Adaptive Protein Evolution in Wild Mice
The relative contributions of neutral and adaptive substitutions to molecular evolution has been one of the most controversial issues in evolutionary biology for more than 40 years. The analysis of within-species nucleotide polymorphism and between-species divergence data supports a widespread role for adaptive protein evolution in certain taxa. For example, estimates of the proportion of adaptive amino acid substitutions (alpha) are 50% or more in enteric bacteria and Drosophila. In contrast, recent estimates of alpha for hominids have been at most 13%. Here, we estimate alpha for protein sequences of murid rodents based on nucleotide polymorphism data from multiple genes in a population of the house mouse subspecies Mus musculus castaneus, which inhabits the ancestral range of the Mus species complex and nucleotide divergence between M. m. castaneus and M. famulus or the rat. We estimate that 57% of amino acid substitutions in murids have been driven by positive selection. Hominids, therefore, are exceptional in having low apparent levels of adaptive protein evolution. The high frequency of adaptive amino acid substitutions in wild mice is consistent with their large effective population size, leading to effective natural selection at the molecular level. Effective natural selection also manifests itself as a paucity of effectively neutral nonsynonymous mutations in M. m. castaneus compared to humans
The Machine Learning Landscape of Top Taggers
Based on the established task of identifying boosted, hadronically decaying
top quarks, we compare a wide range of modern machine learning approaches.
Unlike most established methods they rely on low-level input, for instance
calorimeter output. While their network architectures are vastly different,
their performance is comparatively similar. In general, we find that these new
approaches are extremely powerful and great fun.Comment: Yet another tagger included
Clinical Features and Outcomes of a Racially Diverse Population with Fibrillary Glomerulonephritis
Fibrillary glomerulonephritis is characterized by randomly arranged fibrils, approximately 20 nm in diameter by electron microscopy. Patients present with proteinuria, hematuria and kidney insufficiency, and about half of the reported patients progress to end-stage kidney disease within 4 years. The dependence of patient characteristics and outcomes on race has not been explored. In this study, we describe a cohort of patients with fibrillary glomerulonephritis and compare their clinical characteristics and outcomes with those of patients previously described
A Pediatric Infectious Disease Perspective of SARS-CoV-2 and COVID-19 in Children.
Understanding the role that children play in the clinical burden and propagation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for novel coronavirus (COVID-19) infections is emerging. While the severe manifestations and acute clinical burden of COVID-19 has largely spared children compared to adults, understanding the epidemiology, clinical presentation, diagnostics, management, and prevention opportunities as well as the social and behavioral impacts on child health is vital. Foremost is clarifying the contribution of asymptomatic and mild infections to transmission within the household and community and the clinical and epidemiologic significance of uncommon severe post-infectious complications. Herein we summarize the current knowledge, identify useful resources, and outline research opportunities. Pediatric infectious disease clinicians have a unique opportunity to advocate for the inclusion of children in epidemiological, clinical, treatment and prevention studies to optimize their care, as well as to represent children in the development of guidance and policy during pandemic response
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